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CN-121974719-A - Boron nitride coated high-strength elastic ceramic nanowire aerogel and preparation method and application thereof

CN121974719ACN 121974719 ACN121974719 ACN 121974719ACN-121974719-A

Abstract

The invention discloses a boron nitride coated high-strength elastic ceramic nanowire aerogel and a preparation method and application thereof, and belongs to the technical field of preparation of super-elastic inorganic materials. The method comprises the steps of taking silicon carbide nanowire aerogel or silicon nitride nanowire aerogel as a framework, and uniformly coating boron nitride on the surface of the framework by adopting a chemical vapor deposition method, so that fixed boron nitride nodes are formed between adjacent or contacted silicon carbide or silicon nitride nanowires. The strength of the ceramic nanowire aerogel prepared by the method can reach 787.0 kPa, and the ceramic nanowire aerogel has good recovery capability under 80% compressive strain, and is expected to be used as a material for high-temperature heat insulation, high-performance damping, heat sealing and the like in extreme environments.

Inventors

  • WANG HONGJIE
  • WANG XIAOWU
  • Lu de
  • SU LEI
  • NIU MIN
  • PENG KANG

Assignees

  • 西安交通大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. A preparation method of the boron nitride coated high-strength elastic ceramic nanowire aerogel is characterized by taking silicon carbide nanowire aerogel or silicon nitride nanowire aerogel as a framework, uniformly coating boron nitride on the surface of the framework by adopting a chemical vapor deposition method, and forming fixed boron nitride nodes between adjacent or contacted silicon carbide or silicon nitride nanowires to prepare the boron nitride coated high-strength elastic ceramic nanowire aerogel.
  2. 2. The method for preparing the boron nitride coated high-strength elastic ceramic nanowire aerogel according to claim 1, wherein the silicon carbide nanowire aerogel or the silicon nitride nanowire aerogel is a porous three-dimensional structure constructed by silicon carbide nanowires or silicon nitride nanowires with diameters of 30-500 nm.
  3. 3. The method for preparing the boron nitride coated high-strength elastic ceramic nanowire aerogel according to claim 2, wherein the density of the silicon carbide nanowire aerogel or the silicon nitride nanowire aerogel is 1-10 mg/cm 3 .
  4. 4. The method for preparing the boron nitride coated high-strength elastic ceramic nanowire aerogel according to claim 1, wherein the specific conditions of the chemical vapor deposition method are that the temperature is raised to 600-1200 ℃ from the room temperature, the pressure is 1-20 kPa, the precursors are boron chloride and ammonia, and the deposition time is 0.5-15 h.
  5. 5. The method for preparing the boron nitride coated high-strength elastic ceramic nanowire aerogel according to claim 4, wherein the temperature rising rate is 0.1-10 ℃ per minute.
  6. 6. The method for preparing the boron nitride coated high-strength elastic ceramic nanowire aerogel according to claim 4, wherein the gas flow rate of boron chloride is controlled to be 0.1-10L/min, and the gas flow rate of ammonia gas is controlled to be 0.5-20L/min.
  7. 7. The boron nitride coated high-strength elastic ceramic nanowire aerogel prepared by the preparation method of any one of claims 1-6, wherein the volume density of the boron nitride coated high-strength elastic ceramic nanowire aerogel is 5-100 mg/cm 3 .
  8. 8. The boron nitride coated high strength and elastic ceramic nanowire aerogel of claim 7, wherein the thickness of the surface coated boron nitride layer of the boron nitride coated high strength and elastic ceramic nanowire aerogel is 50-150 nm a.
  9. 9. The boron nitride coated high strength and elastic ceramic nanowire aerogel of claim 7, wherein the stress of the boron nitride coated high strength and elastic ceramic nanowire aerogel is 9.1-787.0 kPa when the compressive strain is 80%.
  10. 10. Use of the boron nitride coated high-strength elastic ceramic nanowire aerogel according to any one of claims 7-9 in high-temperature heat insulation materials, catalyst carriers or filter materials.

Description

Boron nitride coated high-strength elastic ceramic nanowire aerogel and preparation method and application thereof Technical Field The invention belongs to the technical field of preparation of super-elastic inorganic materials, and particularly relates to boron nitride coated high-strength elastic ceramic nanowire aerogel and a preparation method thereof. Background The ceramic aerogel has extremely low heat conductivity coefficient, extremely low density, high porosity, good heat and chemical stability, and great potential in the fields of high-temperature heat insulation, catalyst carriers, filter materials and the like. The traditional ceramic nanoparticle aerogel has the problem of brittleness and lower service reliability. In recent years, elastic ceramic aerogel constructed with one-dimensional flexible ceramic nano-elements (nanowires or nanobelts) overcomes the brittleness of conventional ceramic aerogel and exhibits good deformability and compression resilience. However, the maximum stress of these ceramic nanowires or nanobelt aerogels is typically only tens of kilopascals, and the bearing capacity is insufficient, severely hampering their practical application. The prior strengthening method for the aerogel mainly comprises the steps of introducing a strengthening phase, designing a nanowire three-dimensional network structure, coating the surface of the nanowire, and the like. For example, in 2023 Yan et al, a compressive strength of silicon carbide nanowire aerogel was improved by introducing mullite fibers into the silicon carbide nanowire network (CHEMICAL ENGINEERING Journal 466 (2023) 143089), in 2024 years Zhang Xue et al, a reinforced boron nitride nanoribbon aerogel (CN 115215632B) of polyacrylonitrile fibers, carbon fibers, glass fibers, etc., in 2021 years Lu et al, a silicon carbide nanowire network having a layered structure was assembled by a hot pressing method, which had a strength of up to 5.7 MPa at 20% compressive strain (Journal of THE AMERICAN CERAMIC Society 105 (2022) 2783-2790), in 2022 years Guo et al, a silicon carbide nanowire aerogel lattice of a complex multi-stage structure was customized by 3D printing, and the compressive strength and modulus of the aerogel were improved (CN 114890425B), in 2023 years Su et al, a high-strength flexible ceramic nanowire aerogel (Nature Communications (3) 7057) was prepared by a capillary self-assembly method, and in 2024 years Lu et al, had a compressive strength of up to 35.3535 (2024 10313) by chemical vapor deposition of a silicon carbide nanowire coating on the surface of silicon carbide nanowire network (20235) (No. 35). The method significantly improves the bearing capacity of the ceramic nanowire aerogel, but compromises the excellent rebound resilience of the aerogel to different degrees. Recent researches show that the strength and elasticity (ACS Nano (24) 2024 15950-15957 and CN 114349537B) of the ceramic nanowire aerogel can be synchronously improved by coating pyrolytic carbon on the surface of the nanowire, but the oxidation resistance is poor and the service temperature is limited. In summary, how to obtain ceramic nanowire aerogel with high strength, good elasticity and temperature resistance is a problem to be solved. Disclosure of Invention In order to overcome the defects in the prior art, the invention aims to provide the boron nitride coated high-strength elastic ceramic nanowire aerogel and the preparation method and application thereof, and the technical problem that the existing ceramic nanowire or nanoribbon aerogel cannot be compatible with strength, rebound resilience and temperature resistance can be solved. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: The invention discloses a preparation method of boron nitride coated high-strength elastic ceramic nanowire aerogel, which comprises the steps of taking silicon carbide nanowire aerogel or silicon nitride nanowire aerogel as a framework, uniformly coating boron nitride on the surface of the framework by adopting a chemical vapor deposition method, and forming fixed boron nitride nodes between adjacent or contacted silicon carbide or silicon nitride nanowires to prepare the boron nitride coated high-strength elastic ceramic nanowire aerogel. Preferably, the silicon carbide nanowire aerogel or the silicon nitride nanowire aerogel is a porous three-dimensional structure constructed by silicon carbide nanowires or silicon nitride nanowires with diameters of 30-500 nm. Further preferred, the density of the silicon carbide nanowire aerogel or silicon nitride nanowire aerogel is 1-10 mg/cm 3. Preferably, the specific conditions of the chemical vapor deposition method are that the temperature is raised to 600-1200 ℃ from room temperature, the pressure is 1-20 kPa, the precursors are boron chloride and ammonia, and the deposition time is 0.5-15 h. Further preferably, the temperature rising rate is 0.1-